Flex 2 won't sync to my iPhone 5S due to the required OS by Fitbit

[mywalker2]

I have a 5S Iphone but it supports IOS 12.1.4 version. FitBit now requires 12.2 or later. The Fitbit app on my phone went to the cloud and can't link since Sept. 21. I've tried to reload but it won't allow it. I know my actual fitbit is still tracking because I feel the vibrations when I hit my step goal. 

This Flex 2 version didn't come with a dongle. Is there a way to link it to a computer or a way to find a earlier version for Fitbit? It's been working fine up to last week's update.

Moderator Edit: Clarified subject

[Odyssey13]

 here is something a moderator posted about phones being compatible:

"Please note that your phone or tablet is not on our list of compatible devices. We confirmed that the devices on this list are fully compatible with all features of Fitbit devices and the Fitbit app. While a phone or tablet may not be verified as fully compatible, the Fitbit app may still work with your device. 

We routinely test new devices to ensure full compatibility with Fitbit devices and the Fitbit app, and are constantly working to confirm compatibility with new phone models. Be sure to verify that your phone or tablet meets the minimum operating system requirements.

If your phone supports Bluetooth 4.0, we provide assistance and troubleshooting steps. Because your phone or tablet is not fully compatible with Fitbit devices, we can't guarantee syncing and other Fitbit features. "